Portable electric hack saw



Sept; 28; 1943.

E. W. PLUMB PORTABLE ELECTRIC HACK SAW Filed July 14, 1941 3 Sheets-Sheet 1 lNVENTOR Edwin lt Plumr.

ATTORNEY Sept-2811943. a w. PLUMB PORFPABLE ELECTRIC HACK SAW 3 Sheets-Sheet 2 R O T N w m Edwin WPlumb:

ATTORNEY Filed July 14, 1941 Sept. 28, 1943. a w. PLUMB PORTABLE ELECTRIC HACK SAW fined July-14, 1941 s Sheets-Sheet IN ENTQR Eiiwp'z I'KPZumb:

v ATTORNEY Patented Sept. 28, 1 943 1;"

curren STATES: PATENT OFFICE PORTABLE ELECTRIC HACK SAW Edwin W. Plumb, Morris, ,Conn.

Application I July 14,

2 Claims. This invention relates to metal working and more particularly toa portable hacksaw driven line of travel of the hacksaw frame so that on the forward idle stroke of the blade, the. teeth will be withdrawn from the work to prevent dullingof the hacksaw. 1 A further object is to provide a portable power hacksaw of the above nature in which the hacksaw frame is mounted in anti-friction bearings.

A further object is to provide a power hacksaw of the above nature provided with a stationary anvil member adapted to be held tightly against the work.

Another object is to provide a, portable power hacksaw of the above nature in which the hacksaw will be moved rapidly on the forward idle stroke and more slowly on the rear cutting stroke. A still further object of this invention is to provide an improved portable power hacksaw of the above nature which will be relatively inexpensive to manufacture, simple in construction, compact, ornamental in appearance, and very efiicient and durable in use. I

With these and other objects in view, which will appear as the description proceeds, there have been illustrated in the accompanying drawings several forms in which the invention ma be conveniently embodied in practice. In thedrawings: r Figure 1 is a top plant view'of a portable power hacksaw embodying the features and principles of this invention. i I a Figure 2 is a side view of the same, with the enclosing shield sectioned to expose'the interior working parts thereof Figure 3 is an underside View of the same with the enclosing shield omitted. V Figure 4 is a broken section on the line 4 of Figure 2.

Figure 5 is a section on the line 5-5 of Figure4.

Figure 6 is a broken section on the lineB of Figure 2.

Figure 7 is a section on the offset line 'L-I- of Figure 6. v Figure 8 is an enlargedbroken section on the I line 8-8 of Figure 2.

Figure 9 .is an enlarged broken section onthe line 99 of Figure 2.

Figure 10 is an enlarged broken view looking in the direction of arrowIO in Figure 2. I

Figure 11 is a side view of a modified form. of power hacksaw.

Figure 12 is a side view of sun anotherJform of power hacksaw in which the motor is mounted on an inclined axis,

1941, Serial No. 402,278 (or. 29-73) .IReferring now to thedrawings wherein like reference numerals designate like parts throughout the several views and particularly to thefirst form of the invention illustrated in Figures 1-10 5 inclusive, the numeral I0 denotes a hacksaw blade detachably mounted in the usual manner upon pins Hand I2, carried by holding members l3 and l4-respectively. The holdingmember I3 is permanentlysecured, as by welding; to one leg I5 of a frame I6, and the other member I4 is detachably secured to the other frame leg I! by a clamp screw I8. The frame leg I! passes through a slot l9 inthe member I4. and is clamped thereto by the screw I8 which hasca pointed end I9 15 adapted to engage the leg I! in any one of a plurality of notches provided therein for a purpose to be hereinafter disclosed.

The frame I 6 is provided with two spaced apart pairs of rollers 2i and 22, one roller of each pair 20 being disposed at each side of the frame and being adapted to ride in elongated slots 23 and 24 formed in guide bars Hand 25 respectively, and which are disposed one-at either side of the frame IS. The guide; bars 25 and 26 are 25 secured together by a rivet 21 at their outer ends, and at their inner ends to the casing 23 of an electric motor 29 by screws 30 and 3 I, respectively. By means. of the above construction, the frame I6 carrying theablade I 0 .will be guided in its 30 reciprocating movements over a stationary workpiece 32 with which the saw blade is engaged.

: An inclined handle 33 is provided extending from the motor casing 28, and a switch 34 is conveniently locatedin the handle .33 for operat- 35 ing the motor 29. Another handle35 is provided,

which extends upwardly from and is secured, as by-screws 36 and. 31, to the guide bars 25 and 26 respectively, which it straddles. i i The" blade holding members I3 and i4 are provided with clamp fingers .38 and 39 respectively which'are adapted to clamp the respective ends of a file to the members I3 and I4 by mean of screws 40 and 4| respectively, in case it should be desired to replace the blade II] withka fileinct shown). .The members I3 and I 4 are each also provided, in addition to the centrally located pins-II and I2, with side pins 42, 43, and a4,

(see Fig. 3) whereby the hacksaw blade I0 held thereby may be enabled to cut closer to a shoulder on the work-piece than would otherwise be the case.

. Theblade supporting member I3 has a roller 46 journaled on a pin 41 extending upwardly therefrom and into a slot 48 formed in the frame leg I5 for this purpose. The roller 46 rides between a pair of horizontal bars 49 and 50 'supported in position at their rear ends by vertical frame parts SI and 52 extending downwardly from theguide bars 25 and 26 and at their forward ends by a vertical frame part 53 which exranged to embrace the sides of the part 53 to pre vent misalignment or wobbling. V a v The hacksaw frame I5, IS, IT, the-pin-heldingmembers I3 and I4, and the blade Imamadapted to be reciprocated as a unit with respect to the work-piece 32 by the motor- Zll througlt speed reduction gearing, a crank arm, and a link to-use-a-file-ilr place of the hacksaw blade ID, the

latter willibew removedand replaced with the file which will be clamped to the holding members I3 ranged in accordance with the Whitworth quick returnprinciple, and:ailinkwherebythelblade-will be moved slowly during its: cuttingv stroke: and morerquickly during itsiidle; stroke; 'Inzthis inrstance; the f-vorwardr'stnoke: cfsthehacksaw: isddle and; thez'cuttingitakes; placevoni thev rearward stroke toward; the-anvil54rso that the-works 32;:wi-ll be pressed thereagainstl by. the teethrofi the saav iii during' cutting: I

The. angle; of the hacksa-w' blades Illlr may; be

selectively. adjusted; byt meansiiof the clamp-screw Is3,v to engage in anyone t thenotchesfifl; where-v by, said. hacksaw will be; disposedoutxof parallel with the-path oh the.- rollers. Z-l-thuscausing a tendencyifor the teethxto be-relievedcfrom pressing 0 The on the work: during the idle for-wardstroke;

screwi I8: also, servesito tightenthe: blade Ill-bee tween the pins; I 1|: and :l 2;

The speed: reduction gearing; aboveiref'erredi to includesa pinionfiflaon: the end: ofjthe motor shaft iifltxwhich: is journaled in a:.ball,bearing:5l1sups portedby the; motor endaplate 6:2 (see;,Eig:. 53).."

A side gear 63.; rotatable; Q1133 stud; shaft (341 secured intheplate-M; isiin-imesh withrthe; pinion iilytoibedriven thereby. Erovision: is also-made of; amnion, ;rigidiy' connectedwiththesideigear Gil: meshing! withzav gear; Gil which rotatably mounted on; a stud; shaftfilrergtending from;. and SGuIeditQl theiplate: 32:1 Arpinion 6B) rigidly; se-

rcuredltoit'he', gear fifitmeshesawithi'a gear; Moro tatablymountedzomau circular: stud Till-extending from and; preferably. integ-nalzwith the-plate: 62; The stud I I: ideocentnic to the: axis; ofrthe. motor shaft filband of therpinion lib.

mesa-rile arm J 2;- is;p.ivoted;a't:its innerzendrubon studz shaft I3: extending. outwardly: from; the stud? sconcentrie toithex'axis of themotorgshatt iillzand of they pinion. 59: Therouterend; o-frthe crank arm I2 'is;pivotally;securedbyrazipirrilfs to one end: of a link lli-owhicrr,extendsetherefrom and has itsrother-end piyotallysecunedby arpi'n l-8;.to the blade holdingamembenldr. Theeabmlfi is provided; withan elongated; slot 113 imwhich rides: a. roller, 18: rotatablymounted on. a'. stud shaft I 95: secured tow and: extending: fromkthe goat ill-eccentric to its axis and;theraxis ofthestudcltz A- sheet metal shield indicated in Ei unesil' and 2- may be providedfor; enclosingthe operat mg parts v of the mechanism, to.- protect. the on,- eratorand exclude; dust.

Operation ventionAFigsr 1--l'0 when it is desired to install andil li by: means of the clamp fingers 38 and 39 and clamp screws 40 and 41 described above.

Second. form. (Figure 11) Lnthe modifiediform shown in Figure 11;, the saw blade I0 is secured at one end upon: a pin extending from-.al-leg 8llso-f a; frame 83', .and. at, its otherend upon. apin 88; extending f-ro nra blade holding member 89..slidab1yheldiin alugfiihwhich is securedk'tol thev other leg: 3:4: on the frame 85! by amines. The belt 92 passes-l through arr-elongatedyslot; llfizinithe frame leg 9i whereby'the-saw blade I0 may be adjusted out of parallelwith the pathofxthe roller lea. Theblade may be held between: the pins 85andt 3.8: with any desired degreee'of, tightness by means ofa a: thumb. nut 94 screw-threaded on east-11d 951 extending: fromthe member. 8.5;

In; thissinstanoeithe haeksaw: frame Bil: is reciprocated by means of a horizontal; motor. 55, having arhand-le: 9:7; switch: 9.8,; through a speeili seduction; gearing-,1 connected by a crank arm and-linkagesecuredtottheframe leg 85., The speed} reduction: gearing: includesv a: vpinion 39: on thermoton shaft Mill; which:pinionameshesiwith a gear; I251 having: a shaft: H12; rotatably supported on; azibracket H secured to; the: motor casingrby bolt-s; lflfl. The-shaft M32: extends: from. the. gear 111.11; and hasi.a:worm-; Ill5i secured. thereto. The worm I05 meshes withiaiwormlw-heellfilfiirotatlablr supported: by a studshaft; I'd? extending; frornan anmf. ,l 08.? depending; fromv the bracket; H13;

miles-1103i; rotatablysupported one a stud shnxft-flzfir-extendingr from the WOImi wheel H and eccentric. toiitsyaxis; ridesiin: elongated slot I l I provided in a crank arm-1112'. The crank arm: I l'2;-;is pivoted; at oneend to; the'zbracket'. I83 upon: all pin: H13: andisxpivotally connected: at its otherend by a pin lid to oneendi-ofzalink-IIB: The other-end; of? the link" M5 is-.pi-votally' connectedtoithezframe leg, 85' byaishort'rpin's I It. As in the previously describedform; the frame: 8?? is; guidedbetWeen-theguide-bars. M 9: and-is supported by means of rollers lfillfwhiclr-zride;irrelorr: gatedcslots; I2 I providecb inthe; bars; I [-9.

Thirdlf'orm V (Figure 1 2) therewith-and whi'clrmeshes with a-gear-I32- to will be placed? upon the pins II, and I221 of? the holding r'nembersz l3: and illljxandztheir tightened by; the" screw It The motor: 2.9: wil th'embe started. by manipulation; of the switehrsq, calls; ing th haeksa n madelia:.t. ;,.recioroeate.-; The

drive it. The gear I32 is secured-toan-in'clined shaft I33' which-extends alongside the casing-of the motor I25, being supported thetefromdrrbearings ISA' a-nd I35: A.wr)r-rn= I3 5 secured to the shaft I 33 meshesiwith a worm'wheel;.I ii 'irrotatably supported onastudish'aftil as in; turn supported by a depending arm I39 from a bracketalfilfl; suit ablyzsecured tothezmotorp I225; The wor-mgwheel stud shaft I42 extending from the worm Wheel I31 and which is eccentric to the axis thereof. The roller I4I rides in an elongated slot I43 provided in an inclined crank arm I44, one end of which is pivoted to the bracket I40 by a pin I45. The other end of the crank arm I44 is pivotally connected to one end of an inclined link I46 pivotally secured by a pin I41 to the lower end of a rocker arm I48 which in turn is pivoted by a pin I49 to a horizontal bar I50 extending from the bracket I40. The bar I50 has another rocker arm I5I pivoted to it adjacent its remote end by a pin I52. The lower end of the rocker arm I5! has a blade-holding member I53 pivoted to it by a pin I54 and the arm I48 also has a blade holdins member I 55 pivoted to it by the pin I41. The blade I is secured to the members I 53 and I55 by pins I56 and I 51 respectively. The upper ends of the rocker arms I48 and II are connected together by a rod I58 parallel to bar I50 and is pivoted at one end to the arm I48 by a pin I59 and at the other end to a block I60 slidable in a slot IBI, provided in this end of the rod I58, and adjusted by means of an adjusting thumb screw I62 engaging said block I60. A pin I63 connects the block I60 to the upper end of the rocker arm I5I. By means of this construction it will be seen that adjustment of the screw I62 will tighten the blade I0 between the blade holding members I53 and I55.

A pair of work-engaging anvils are provided in this instance and comprise a demanding bar I64 adjacent the-rocker arm I48 and which is suitthe bar I50, and a bar I65 having clamp jaws I66 adapted to be clamped to the bar I by a bolt I61.

While there have been disclosed in this specificationseveral forms in which this invention may be embodied, it is to be understood that these forms are shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosures, but may be modified and embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new and for which it is desired to secure Letters Patent is:

1. In a portable power-driven hacksaw adapted to be carried in the hands of an operator, a frame having an electric motor n'gidly mounted thereon, a pair of rocker arms pivoted at spaced points on said frame, said rocker arms being adjustably connected together at their upper ends by a horizontal link, the lower ends of said rocker arms being connected by a hacksaw blade, and means for drivingly connecting the lower end of one of said rocker arms to said motor for reciprocating said hacksaw blade, said frame having an elongated portion extending beyond the pivot points of said rocker arms to support said motor.

2. A portable power-driven hacksaw as defined in claim 1, in which said frame has an integral anvil to engage the work being sawed, an adjustable anvil slidable on said frame, and means to lock said slidable anvil in any desired position on said frame.

' EDWIN W. PLUMB. 

